Galactokinase deficiency

Disease Overview

Galactokinase deficiency (GALK), a mild type of galactosemia, is an inherited disorder that impairs the body’s ability to process and produce energy from a simple sugar called galactose. If babies with GALK eat foods containing galactose, undigested sugars build up in the blood.[14968] Galactose is present in many foods, including all dairy products, many baby formulas, and some fruits and vegetables.[14968][3533] Children with GALK who are not treated with dietary therapy develop cataracts in the eyes, but otherwise they typically do not have long-term health problems.[3533] Rarely, a child with GALK will have pseudotumor cerebri, a condition which mimics the symptoms of a large brain tumor when no brain tumor is present.[14975][14976] This is thought to be caused by increased pressure in the brain from cerebrospinal fluid (CSF) due to elevated levels of a galactose product in the CSF.[14975] The severe medical problems that occur with “classic” galactosemia (type 1), such as liver, kidney, and brain damage, typically are not present in people with GALK.[3533][14975]

GALK is caused by mutations in the GALK1 gene and inheritance is autosomal recessive.[3533] The disorder may be suspected in babies with an abnormal newborn screening result, or in babies with cataracts. The diagnosis can be confirmed with biochemical and molecular genetic testing.[14968][14975] The treatment is dietary therapy, which involves taking calcium supplements and restricting galactose in the diet throughout life to prevent cataracts.[14977] If cataracts develop, they usually resolve with dietary therapy.[14968][14975] Children with GALK should have their growth monitored, and both children and adults should consult with a dietitian and have regular eye exams.[14977] 

Synonyms

• GALK deficiency
• Galactosemia 2
• Hereditary galactokinase deficiency
• Galactosemia type 2
• Galactokinase deficiency galactosemia
• GALK-D